This invention relates to apparatus for supporting a coil material supply device used in a pressing line.
With a high-speed pressing operation, the time used for intermittently feeding a coil material has become short, and the coil material is repeatedly fed and stopped in such a short time. As a result, the coil material vibrates by an exciting force exerted thereon, so that a wavy phenomenon called "fluttering" occurs. When such fluttering of the coil material occurs, not only an excessive burden or load is imposed on a feed device, but also the coil material is bent or damaged. To prevent this, it has been proposed to provide a buffer section called "looper" at the coil material.
FIG. 6 shows a U-shaped looper, and that portion of a coil material 101 lying between an uncoiler 102 for unwinding the coil material 101 and an intermittent feed device 104 mounted on a mechanical press 103 has a U-shaped buffer section. FIG. 7 shows an S-shaped looper, and that portion of a coil material 101 lying between an uncoiler 102 for unwinding the coil material 101 and an intermittent feed device 104 mounted on a mechanical press 103 has an S-shaped buffer section.
In such a pressing line, various kinds of coil materials having different physical properties and shapes are used, and a feed pitch often need to be changed, and the operation speed often need to be changed, for example, into a higher speed. In such a case, taking into consideration the degree of bending of the coil material, as well as the alleviation of the influence of an inertial mass and an inertia force, the optimum condition for the coil material supply device must be set or determined depending on the above various changes.
With the coil material supply device utilizing the conventional U-shaped looper or S-shaped looper, however, the following problems have been encountered:
(1) The positional relation of the coil material supply device to the intermittent feed device is determined by the position of installation of this supply device, and is basically fixed. Therefore, it has been difficult to vary the position in accordance with a change of the feed condition.
(2) The position of guides or rollers of the coil material supply device is determined by an initial setting, and therefore it has been difficult to exchange the guides with other guides of a different shape, or to change the position of the rollers in accordance with a change of the feed condition.
(3) The condition of setting of the U-shaped looper or the S-shaped looper can not be changed during the operation of the pressing line, and therefore it has been difficult to find the optimum condition for the coil material supply device.